1. Field of the Invention
This invention relates to a device for the protection of an electronic installation against the interference generated by phenomena affecting the outer environment in which the installation is placed.
It applies notably, though not exclusively, to the protection against lightning, or even electromagnetic interference (EMI), of electronic installations situated on board an aircraft.
2. Description of the Prior Art
It is known that, at present, it is increasingly more common for these installations to have modular structures using racks within which modular functional elements can be engaged in drawer-like fashion.
These modular elements are connected to one another and to the exterior (aircraft links) by means of an interconnecting circuit provided at the back of the rack.
This interconnecting circuit does of course comprise connection elements susceptible of cooperating with corresponding connecting means integrated into each modular element.
Hitherto, these installations were protected (at the user's request) against lightning and electromagnetic interference by means of protective circuits integrated into the electronic circuits of the modular elements.
Experience has proved that this solution has numerous drawbacks.
It firstly requires specific designing of the electronic circuit boards of the modular elements, which will differ depending on whether or not the above-mentioned protection is ensured.
Protection of a modular element not originally protected therefore implies a change of printed circuit board, i.e. a costly intervention that can only be performed by a specialist.
Moreover, in view of the integration thereof into the electronic circuits of the modular elements, protective circuits process interference within the very circuits they are intended to protect, to the extent that, paradoxically, these circuits are even further exposed to these interferences.
Another drawback of this integration consists in that it can be difficult to test these protective circuits.
Furthermore, it so happens that this solution is poorly suited to the solving of heat dissipation problems occurring notably when, subsequent to a stroke of lightning, the excess current running through the protective circuit causes a sudden and intensive temperature rise inside the modular element.